Improvements in footwear technology may have benefits for a variety of activities. Footwear design may benefit wearers for purposes of ordinary, day-to-day use. Footwear design may also benefit wearers who work in physically challenging conditions requiring bodily protection, or engage in recreational outdoor activities such as hiking or fishing. Some improvements in footwear technology may be advantageous to generally athletic activities such as running, or to specific sports, such as football, baseball, basketball, hockey, soccer, tennis, golf, lacrosse, or cricket.
An article of footwear may in turn have various parts subject to improvement. For example, a conventional article of footwear may include an upper and a sole structure. The upper may be formed from one or more of a variety of material elements (e.g. textiles, leather, synthetic leather, and foam materials), and may define a void that securely receives the foot of a wearer and positions it with respect to the sole structure. The sole structure may be secured to a lower surface of the upper, and may have a layered configuration that includes a comfort-enhancing insole, a resilient midsole formed from a polymer foam, and a ground-contacting outsole.
A polymer foam material within a sole structure may include a plurality of open or closed cells that deteriorate following repeated compressions. The effects of this deterioration may be decreased by incorporating a fluid-filled chamber into the sole structure. The chamber may be formed from a polymer material that is sealed to enclose a fluid, and may be encapsulated within the polymer material, or may be located above or below it, or may form any portion of the midsole. Fluid-filled chambers suitable for such footwear applications may be manufactured by thermoforming techniques.
The sole structure may serve to attenuate ground reaction forces, to provide traction, and to control various foot motions such as pronation. The upper and the sole structure may cooperatively provide a comfortable structure to benefit a wearer engaged in any of a variety of activities.
Meanwhile, an individual wearing an article of footwear and engaged in an athletic activity or sport may make sudden stops or changes of direction, which may subject the upper of the footwear to various deforming forces. For example, an individual playing a game of football or basketball may need to rapidly change direction to avoid another player. Such movements may subject an article of footwear to various deforming forces, and may also subject an ankle of the individual to various stresses.
At the same time, an individual may be a member of a team, or may be one individual competitor among many individual competitors. Whether as an individual competitor or a part of a team, the individual may benefit from an increased ability to identify themselves. Identification may help team-mates locate an individual playing on a field, for example, to the benefit of the team during the game. Similarly, individual players may also benefit from being made more easily recognizable to referees, coaching staff, or others.
Therefore, there exists a need in the footwear art for improvements that may mitigate various deforming forces to which an article of footwear may be subjected and various stressing forces to which an ankle of an individual may be subjected. There also exists a need for improvements that may help to identify an individual wearing the article of footwear.